I don't have a ton of experience with drum brakes aside from changing the shoes. Recently, my automatic tensioner broke, so I am forced to manual adjust the brake tension. I was under the impression, that on the back of the drum under the axle tube there was a rubber grommet, and behind the grommet a flat head screwdriver could be inserted to some how adjust the brake tension. I tried this, and I had no luck locating anything that could allow me to adjust the brakes. I couldn't even get the drum OFF the driver's side. Too much tension or something. And yes, the parking brake was off.

How can I adjust my brakes manually?

 

Look at the opening where the little rubber plug goes on the other side. Inside you will see a wheel with notches on it this it the adjuster mechanisum. You have probably turned the other side too far the wrong way and may have actually tightened it. You sort of rachet it one way or the other by prying on the teeth to make the wheel go one way or the other. When you can rotate the brake drum you know that the shoes are free. If you pulled on the brake drum without getting the shoes loose first as I said you know you turned the adjuster the right way when you can turn the drums you can also actually get them cocked against the drum. In that case yes a litle hammer to just giggle them free might help--dont pound on it and dont pound directly down on the bearings. . But if the shoes are not backed off you cant get the drum off. The other thing is the drum fits agains the axel flange often they are rusted together there. A plumbers torch is a good item to have starts campfires well too. You can get propane or map gas bottles (yellow bottle) and heat the area around the spot where the axel flange must meet the drum this would be the circumferance around the center of the the axel but on the drum. Turn the drum slowly while you heat this area you can use PB blaster or some other kind of rust inhibitor. spray around the center of the hub where both the hub and the drum meet as it cools. This can help break the rust. Tap from the back side of the drum on one side then the other in the direction that the drum would have to come off keep at it left side then right side. But first you have got to back the adjuster off, Inside you will probably find a cable with sort of an arm on it this goes on a certain way to ratchet the adjuster to tighten the adjuster every time you pull the parking brake it attempst so adjust the shoes.
So in theory pulling on the parking brake could make the shoes tighter. But also I dont ever pound on a bearing especially in a direction that could flatten the rollars or ball bearings. You can hammer on the drum some in the opposite direction of the center of the axel in the normal direction that the bearings would come out and the drum goes off.